Fukagu and Mikoto talking with Sasuke, Madara's 4 brothers would be like "Yo bro you seem to be alright. Hey Izuna where are your eyes?" Other Uchiha's would rage because of Itachi and Obito's parents would be all "You little brat! We told you like hundred times that don't trust Madara and what are you doing? Why do you have rinnegan and what about those clothes! You lack Uchiha swag!"
Yeah what an reunion and then Obito would probably chance they all in to a mindless puppets. But i don't think that Uchiha clan is good army. Shisui, Izuna, Itachi, Madara and Kagami maybe but the others got only sharingan.